I’m reading Graham Pullin’s book, Design Meets Disability. He starts out with a quote from Charles Eames: “design depends largely on constraints.” Charles and Ray Eames designed, among other things, the iconic molded plywood chairs manufactured by Herman Miller.
I love this quote. Much of the work of a web design professional seems to be about explaining and demonstrating the constraints of digital environment. There’s something about the plasticity of digital that leads to an “anything is possible” mentality. After all, in software development most everything is a simple a matter of programming. And though this expression is intended to be ironic, in many ways it is true. Much is possible, given the necessary time and knowledge. But just because something is possible doesn’t mean it’s appropriate, given the constraints of the environment.
Many factors constrain the form of a chair: its materials, variability in human form and function, its physical and cultural context. These are broadly understood by designers and consumers. For the most part, even the most innovative designs produce chairs we can sit on.
The factors that constrain digital designs are less well understood, in part because they are in a constant state of flux. Also, digital design is a new profession, unregulated and un-credentialed, and lacks a shared vocabulary and common understanding of the requirements of a safe, stable, and accessible environment. The resulting disorder produces unnecessary constraints, one of the more vexing of which is variability.
I am currently working on an HTML email, nesting tables just like old times, and am dismayed by the variation in rendering across clients and platforms. When software developers do not adhere to constraints, such as the need for consistent rendering, web designers end up spending much, if not most, of their time creating designs that will survive variable platforms.
So I should qualify my endorsement of constraints by saying I enjoy working with real constraints, like a limited font selection and variable window widths. I don’t enjoy wasting time dealing with inconsistent rendering.
The discipline of design is in observing and working with constraints to produce an experience that people can settle into and enjoy, with ease and comfort. The sooner we can bring discipline and respect for constraints to the digital environment, the better.
Sarah Horton 
Comfort and ease of use are paramount considerations for button features, but strong geometric visuals were also a key objective throughout the button design concept stage for this case. In the theory of design aesthetics, contrast and cohesion are equally important and the use of circular interaction points created the perfect balance between these two constraints.